Desert Twinbugs

Leaves: petioles 5–20+ mm; blades mostly 10–30(–120) × 3–20(–30+) mm. Peduncles 1–3+ mm. Involucres 2–3+ mm. Phyllaries: outer ± lanceolate, ± herbaceous, sericeous to strigillose, inner ultimately obovate to ± orbiculate, usually ± cucullate, scarious to membranous, usually glandular-pubescent, each ± investing a cypsela. Paleae 1.8–2+ mm. Functionally staminate florets: corollas 2.5–3 mm. Cypselae 3–8+ mm. 2n = 36.

Dicoria brandegeei A. Gray; D. canescens subsp. brandegeei (A. Gray) Cronquist; D. canescens var. brandegeei (A. Gray) Cronquist; D. canescens subsp. clarkiae (P. B. Kennedy) D. D. Keck; D. canescens subsp. hispidula (Rydberg) D. D. Keck; D. canescens var. hispidula (Rydberg) Cronquist; D. canescens var. witherillii (Eastwood) Cronquist; D. clarkiae P. B. Kennedy; D. paniculata Eastwood

Dicoria wetherillii Eastw. Proc. Calif. Acad. II. 6: 299. 1896
An annual, resembling D. canescens; stem canescent; upper leaves spatulate, hirsute-
canescent; heads numerous in leafy panicles; involucre hemispheric, 3-4 mm. broad; bracts 5,
elliptic, white-hispid; paleae subtending the pistillate flowers membranous, intricately veined,
glandular-pubescent, orbicular, hooded, 10-15 mm. long, 10 mm. broad, enclosing the achenes;
staminate flowers several; corollas funnelform, pubescent, longer than the bracts; pistillate
flowers usually solitary; achenes oblong, 8-9 mm. long, 4 mm. wide, mottled with brown, with
scattered hairs and yellow glands; margin pectinate, somewhat scarious, about 0.5 mm. wide.
Type locality: Along San Juan River [Colorado or Utah]. Distribution: Known only from the type locality.

Dicoria canescens A. Gray; Torr. Bot. Mex. Bound. Surv
87. 1859. Dicoria calliptera Rose & Standley, Contr. U. S. Nat. Herb. 16: 18. 1912.
An annual herb, becoming woody at the base; stem 3-10 dm. high, striate, hispidulous; lower leaves opposite, petlcled, with lanceolate dentate blades; upper leaves alternate; petioles about 1 cm. long; blades oval or suborbicular, 1-3 cm. long, densely white-hirsute on both sides, those of the flowering branches similar but much reduced; heads numerous in leafy panicles; involucre hemispheric, 3-4 mm. broad; bracts 5, elliptic, white-hispid; paleae subtending the pistillate flow r ers membranous, orbicular, glandular-puberulent, and glandular-erose on the margin, in age becoming 6-8 mm. broad; those subtending the staminate flowers slender, slightly clavate; staminate flowers 5-7; corolla funnelform, sparingly pilose; style very short; stigma minute; pistillate flowers 2; achenes 6 mm. long, oblong, slightly pilose at the apex and along the outer rib, dorsiventrally flattened with dentate wings on the margins and low ribs on the faces, the ridge on the inner face often developed into a low crest near the apex.
Type locality: Sandy desert of the Gila, Arizona.
Distribution: Arizona, southeastern California, and southern Utah.

Dicoria paniculata Eastw. Proc. Calif. Acad. II. 6: 298. 1896
An annual herb, branched from the base; stem 3-5 dm. high, with ascending branches, hispid-strigose; leaves opposite and alternate, entire or sparingly dentate, 2-S cm. long, tripleribbed or the upper 1-ribbed, canescent, hispid-strigose; heads in leafy panicles; involucre
about 4 mm. broad, campanulate; bracts 5, oblong, distinct; paleae subtending the pistillate
flowers orbicular, truncate or retuse, glandular, membranous at the edge, ciliate and slightly
strigose; those subtending the staminate flowers filiform-clavate; staminate flowers 9 or 10, the
corolla slightly hispid; pistillate flowers 2; achenes oblong, hairy, 6 mm. long, 2 mm. wide,
dark-brown, irregularly dentate on the margin with horny teeth.
Type locality: Sandy flats along the San Juan River, near the junction of McElmo Creek, southwestern Colorado.
Distribution: Southwestern Colorado and northwestern New Mexico.

Dicoria hispidula Rydberg, sp. nov
An annual herb, becoming woody at the base; stem 2-10 dm. high, divaricately branched, puberulent and hispidulous with pustulate-based hairs; leaves mostly alternate, short-petioled ; leaf-blades suborbicular, 1-2 cm. long, canescent-hirsute and with scattered stiff hairs; heads numerous in leafy panicles; involucre hemispheric, 3-4 mm. broad; bracts 5, elliptic, whitehispid; paleae subtending the pistillate flowers elliptic or oval, 4-5 mm. long, hispidulous and somewhat glandular, greenish-white; those subtending the staminate flowers filiform, sparingly hairy ; staminate flowers 5 or 6 ; corolla funnelform, sparingly pilose ; pistillate flowers mostly 2; achenes somewhat oblanceolate, slightly hairy, 4-5 mm. long, dorsiventrally flattened, slightly ribbed on the faces; margin dentate with small, somewhat horny teeth.
Type collected on the Whitewater Desert, California, 1881, 5. B. &" W. F. Parish 7 (U. S. Nat. Herb.).
Distribution: Southern California.

Dicoria canescens is a North American flowering plant in the family Asteraceae known by several common names including desert twinbugs and bugseed. This is a desert plant of the southwestern United States and northwestern Mexico, found in Sonora, Baja California, southern California, Nevada, Arizona, Utah, southwestern Colorado, and northwestern New Mexico.

Dicoria canescens forms thickets of many individuals in the desert sand. The distinctive lower leaves are long, pointed, sharply toothed, and covered in a coat of thin white or gray hairs. The upper leaves are smaller and more rounded. One plant can produce several whitish flower heads containing disc florets but no ray florets. Sometimes the heads form closely associated pairs, a characteristic which is the origin of the common name "twinbugs".